The invention relates to a cutting mechanism for severing elongate fibre reinforcement material in composite material lay-up equipment.
Fibre composite components are frequently used for applications requiring a combination of light weight and strength, for example in sports equipment and in aerospace components. Most fibre composite manufacturing processes require successive layers of fibre reinforcement material to be applied to an article or a mould in a lay-up process. A matrix material is either pre-applied to the fibre reinforcement material (pre-impregnated, or “pre-preg”) or is subsequently applied to the reinforcement material before curing in or out of an autoclave. Recent manufacturing developments have allowed the lay-up process to be performed automatically.
Three exemplary automatic composite manufacturing processes are Automatic Tape Laying (ATL), Automatic Fibre Placement (AFP) and automatic filament winding. Briefly, ATL relates to the application of a tape comprising fibre reinforcement material to an article. The tape typically comprises unidirectional fibres which are pre-impregnated with matrix material (e.g. epoxy resin). Successive tape layers are typically applied at different orientations from one another to form a ply structure. The tape is typically applied to the article by an applicator roller.
In AFP, the fibre reinforcement material is applied to an article in the form of a “tow”, comprising a plurality of individual fibres, or multiple “tows”. A “tow” may be a narrow width of tape slit from a wider tape. AFP is typically more suitable for complex parts having a higher degree of curvature or non-uniform curvature. The fibres are typically pre-impregnated with matrix material or drawn through a bath of matrix material. A course or series of “tows” is typically applied to the article by an applicator roller.
Automatic filament winding differs from AFP in that the article typically functions as a rotating mandrel and the lay-up equipment typically traverses the mandrel to apply a tow of fibres in tension over the mandrel surface. The angle at which the tow is laid over the mandrel can be adjusted between successive passes of the mandrel such that successive layers lie at different orientations from one another to form a ply structure and to influence the properties of the component (e.g. improved compressive or tensile strength of the manufactured component). The tow of fibres is typically applied to the article by virtue of tensile forces in the tow between the mandrel and an applicator roller of the lay-up equipment.
In all of the above processes it is necessary to sever (or cut) the tow or tape of fibre reinforcement material (whether pre-impregnated or not) at the end of the process, or at the end of a stage in the process.
However, the cutting mechanisms used in known composite lay-up equipment are bulky, which causes the equipment to be bulky at the tip region. A bulky tip region may limit the complexity of the articles to which fibre reinforcement material can be applied by the equipment, since it may not be possible to manipulate the tip region over high curvature or other hard-to-access parts of the article.
It is therefore desirable to provide improved composite lay-up equipment which is less bulky in the tip region and to provide an improved cutting mechanism for use with the equipment.